The invention is based on an air brake system as defined hereinafter.
An air brake system of this kind is known (German Offenlegungsschrift 37 30 779). In such known air brake systems, the problem exists that particularly in the phase of brake pressure increase, before the onset of regulation by the anti-skid assembly, major differences in synchronism between the control pressure and the brake pressure arise. During excessively forceful braking, when the anti-skid assembly comes into play, "pressure maintenance" in the control pressure chamber of the relay valve is far from bringing about any "pressure maintenance" in the brake pressure chamber of the relay valve. As a result, the brake pressure in a pressure maintenance phase rises still further, so that when the anti-skid assembly comes into operation, often very marked wheel speed fluctuations occur. At the least, this endangers the lateral guidance of the motor vehicle.
A similar effect arises in the brake pressure reduction phase, when the pressure in the control chamber of the relay valve is reduced via the magnetic valves, in which case this pressure reduction takes place faster than the pressure reduction in the brake line.